Concrete piercing fuse



J. A. TAYLOR ETAL 2,873,677

CONCRETE PIERCING FUSE Feb. 17, 1959 2 Sheets-Sheet 1 Filed Deo. 21, 1951 7 /f 7 70 j E 27 zo United States Patent coNcRnrE PIERCING FUSE `lohn A. Taylor, Rockaway, N. Y., Selm S.- Podnos, Washington, D. C., and Herbert C. Frazer, Manchester, Conn., assigno'rs' to' the United States of America as represented by the Secretary' of` the Army ApplicationDecember 21, 1951', Serial No'. 262,776

13 Claims'. V(Cl'. 102'75) 'trifugal force' to lock the fuse' elements insafe position upon setback, until the' projectile' is' free' ofthe bore', when setback forces cease. Y.

`In ordinary missiles, whichV commonly carry high explosive charges, it is desirable thatV each missile remain unarmed or safe under ordinary' conditions of handling or if dropped; Also desirable is the expedient of 'providing a' precautionary safety device tolock the arm"- ing mechanism in safe position' until the' missile has left the gun bore', in' order to insure maximum safety of the operating personnel. If' the missile vis' ,toV be' used for specialized purposes, as' for example in destroying con'- crete" pill boxes, or other impenetrable objects such as tanks, a momentary delay in explosion afterv impact is a desired objective, in order thatA the" full' blast effect of the explosion maybe brought to bear' upon the target to: be destroyed.

It is therefore an object of thisV invention to provide a fuse' for a spin' stabilized projectile which is armed by centrifugal' force', lbut which is locked in' safe position by the forces of setback until the projectile leaves the gun bore, when setback ceases'.

It is also4 an' object of this invention'to provide a fuse in which the centrifugal force responsive means acts as av safety device to preclude arming of. the fuse due to impact caused by accidentally, dropping4 a projectile.

,It is also' a further object of this' invention to provide .afuse' having aj plurality' of sleeves'. axiallyl slidablje rel'- atiVe to one another to fully arm the'flse at' impact and incorporating an' anti-creep device comprising detent means associated with two of the sleeves to lock the sleeves, together while the projectile is in flight.'

It is` also a further object of this invention to provide a fuse having an arrangement oflparts to insure a momentary delay in explosion after impact inorder to reap the maximum advantage off blast propagation.

With' these and'other objects in" view, which will become apparent asf the following specification develops, reference is made to the accompanying: drawing. in which':

Figure 1 is a longitudnial section taken: through the vforward` endY of a projectile provided with the novel fuse which is` the subject of. this invention" and: showing the fuse with elements in normal position` before firing.

Figure 2 is a section looking. in the direction of arrows 2-2 on Figure' 1.

Figure 3` is a longitudinal section taken on line' 3 3 ofFigure 2. Y

VFigure 4.is` a'- transverse 'section taken. on' line 4--4 of Figure 3.

Figure 4a is a fragmentary detail of the pin for mount- Ving the centrifugally responsive spring arms;

Figure 5 is a view similar to Figure 1 but with the elements in position at setback.

Figure 6 shows the same parts in position at cessation of setback and when the projectile is in night.

Figure 7 shows the position of the fuse elements at impact, and

Figure 8 showsA the position of the fuse elements at maximum penetration or complete'perforation.

Figures9-ll illustrate a modication of the fuse shown in Figures 1-8.

Referring to the drawing wherein like parts in the different gures` are represented by the same numeral, the projectileis provided with a solid steel forwardly, tapering main body portion 1 circumferentially recessedl at 12a to accommodate a wind shield or nose 2 secured in any convenient manner to the main body portion to complete the forward ogive of the projectile. The main Vbody portion 1 includes a second rearward and deeper circumferential recess 1b externally threaded to screwthreadably receive the projectile casing 1c which contains (not shown) the main explosive charge, primer and detonator as is well known.

The main body of the fuse is provided at its rearward portion with an axial' bore 3 circumferentially stepped as at 4' to form a second axial bore 5' of reduced diameter, in which is pressed or secured in any conventional manner a cylindricali sleeve 6l to make a tight iitwith the main body portion of the fuse. Cylindrical sleeve 6 is circumferentially stepped at 7, 8 and' 9 to provide a plurality of recesses 10, 11 and 12, forwardly axially increasing in diameter to accommodate the moving parts ofV the fuse asl subsequent to be described.

pair of concentric cylindrical sleeves'13 and 14 are received respectively within` recesses' 10 and 11 and are axially slidable relative to one another. When the fuse is' in normal or safe condition, outer sleeve 14 extends between; stepped portions or shoulders 8 and 9, and inner sleeve 131 which is the longer of the two sleeves, abuts shoulder 7 on its rearward end and forwardly extends beyond the forward end of sleeve 14 partially into recess 12 as at 15. The forward end of sleeve 14 is also provided with a rearwardly inwardly beveled face 15m. A at plate or disc 16 is secured in any convenient manner' to the forward end of sleeve 6 with its forward face abutting the forward wall of bore 5 to act as a closure member for recess 12, and an eccentrically located pin 16a having one end press fitted into plate 16 extends rearwardly into recess'12 to act as a pivot for two outwardly bowed'l spring arms 17 and 18v swingable in opposite directions under the influence of centrifugal force. In contracted or normal position spring arm free ends 19 and 20 abut a stud 2l also secured to plate 16 in any convenient manner to extend rearwardly into recess ft2 andv at a location diametrically opposite pivot pin 16a. Spring arms 17 and- 18 are normally biased into contracted position by counterbiasing springs 22 and 23 coiled around pivot pin 16a and having one end anchored to the spring arms and the other end secured to closure plate 15. Sufficient clearance is provided between the contracted spring arms and the inner peripheral wall of recess 12 to allow for counter-pivoting and expansion of the spring arms when centrifugal force acts on the projectile. Spring arms 17 and 18 are supported on pivot pin 16a so as to be axially slidable between stops 24 and 25 secured to the pin and for a purpose to be later described, however, in normal position springs `22' and' 23 bias the spring arms forwardly on the pivot pin and against forward stop 2S, as seen in Figures 3 and 4a.

A third cylindrical sleeve or firing pin guide hub 26, secured as at 27 to the wall of a bore formed in dat plate 16 extends rearwardly a substantial distance into the bore in the inner movable sleeve 13 and is concentric therewith and radially spaced therefrom to form an annular chamber 28 to receive a coil spring 29. Axially slidable within the bore of sleeve or hub 26 is a rearwardly directing ring pin 30 about which is xed an enlargement or collar 31 having a central cylindrical portion 31a abutting the inner peripheral wall of sleeve 13 to guide the ring pin, -a rearwardly directed beveled face 32 and a forwardly projecting reduced cylindrical portion 33, but of a diameter greater than ring pin 30. Sleeve 13 is provided with a plurality of equiangularly spaced holes 34 to receive the major portions of detent balls 35. The preferred embodiment shows 3 balls as clearly seen in Figure 2, however, the number may be varied as desired. An inward portion of each detent ball abuts against the beveled face 32 of enlargement 31 to releasably lock the ring pin in safe position until the projectile strikes the target. In this position spring 29 is compressed between the forward face of enlargement 31 and the rear face of plate 16 to bias firing pin rearwardly so as to leave a clearance between the forward end of the firing pin and the forward wall of bore 5 in the fuse body and to retain sleeve 13 against shoulder 7. Outer sleeve 14 is provided with a circumferential groove 36 in its inner wall for receiving a small portion of detent balls 35, thus preventing sleeve 14 from creeping forwardly in ilight and also to retain it in rearward position against shoulder S. Groove 36 is made suiciently deep so as to permit the forces developed at impact to overcome the resistance of the detent balls to completely arm the fuse. Impact caused by blows in handling or by inadvertent dropping of the projectile is not sufficiently strong to overcome this resistance.

The operation of the fuse is as follows: Figures 1 and 3 show the relative location of the moving parts of the fuse in normal position and before the projectile is ilred. If in handling, the projectile were to be dropped on its nose or struck a sharp blow, spring arms 17 and 18 would prevent sleeve 14 from sliding forwardly to arm the fuse even if the impact were suicient to overcome the resistance provided by detent balls 35 resting in groove 36. When the projectile is fired the initial setback forces will cause the spring arms to slide rearwardly on pivot pin 16a until rearward stop 24 is encountered. Centrifugal action has not yet become effective to swing the spring arms outwardly, and they will abut the beveled surface a of outer cylinder 14. In this position centrifugal force will have no effect on spring arms 17 and 18 since they are locked against pivoting by beveled surface 15a. This condition is clearly shown in Figure 5. When the projectile is free of the gun bore and when setback forces have ceased, centrifugal force and linear acceleration acting on spring arms and against beveled surface 15a, will cause the arms to creep forward on pivot pin 16a until they are no longer restrained whereupon they will swing outwardly to assume the position shown in Figure 6. This position may be designated as semiarmed, and the anti-creep device consisting of groove 36 in sleeve 14, holes 34 in sleeve 13, detent balls 35 and beveled face 32 on the firing pin enlargement, will serve to retain the moving parts in this position until impact. At impact the resistance provided by detent balls in groove 36 is overcome and sleeve 14 is forceably moved forwardly until its forward edge abuts plate 16. Sleeve 13 and tiring pin 30 are also driven forward by the impact until the forward face of reduced portion 33 of the firing pin abuts vthe rear annular Wall of fixed sleeve 26, thus compressing spring 29. This is the fully armed position as clearly seen in Figurer7, and as soon as the forces of inertia resulting from impact are overcome, ,spring 29 will expand and the beveled face 32 will 2,878,677 l, y l. ,4

exert pressure on the detent balls to force them suiciently into the rearward portion of recess 8 vacated by the forwardly sliding sleeve 14, to free the firing pin so that it can move rearwardly under inuence of spring 29 to strike the detonator (not shown) usually provided in projectiles as is well known.

A projectile incorporating the above described novel fuse has been found to be extremely elfective in destroying concrete pill boxes. The momentary delay in explosion of the projectile after impact provides time sucient to enable the projectile nose to either pierce the wall of the target or to become imbedded in it so that the full effect of the blast is propagated throughout the structure to be destroyed.

The modification illustrated in Figures 9, 10 and l1 though differing in some of the structural details is similar in action to the fuse illustrated in Figures 1-8. Figure 9 illustrates the fuse as assembled and on setback, Figure 10 illustrates the relative position of parts following cessation of impact forces and Figure 11 is a section taken on line 11-11 of Figure 9. Referring to the drawings where similar numbers have been utilized to designate parts similar to the species of Figures 1-8, the fuse is represented by a cylindrical member 6 which is forwardly and outwardly stepped to provide shoulders 7 and 8 forming annular recesses 10 and 11 for receiving respectively, relatively axially slidable sleeves 13 and 14 concentrically arranged. Outer sleeve 14 is the shorter of the two sleeves, is relatively slidable with respect to sleeve 13 and in unarmed position is located rearwardly in recess 11 so as to leave the forward portion of recess 11 unoccupied. Inner sleeve 13 on the other hand occupies the entire recess 10 and is not movable. In communication with this forward portion of recess 11 are two opposed substantially radial bores and 41 which are slightly rearwardly sloped and in which are received the centrifugal force responsive locking mechanism, as now described. Spanning the outer ends of bores 40 and 41 and normal to the side wall of the bores are plates 42 and 43 to which are secured in any convenient manner inwardly directed studs 44 and 4S. Received in the bores and slidable therein are pins 46 and 47 having integral therewith outwardly depending sleeves 48 and 49 which `in outermost position lie with the outward ends of sleeves 48 and 49 abutting plates 42 and 43. 'Ihe outer Wall of the sleeves contact the wall of bores 40 and 41 whereas the inner walls of sleeves 48 and 49 are spaced from the surfaces of studs 44 and 45 to form chambers 50 and 51 for receiving springs 52 and 53 which are coiled about studs 44 and 45 and in unarmed position bias the pins 46 and 47 and integral sleeves inwardly into recess 11 to abut the ends of cylinder 14. As plainly seen in Figures 10 and 11, the modification is also provided with the anti-creep device comprising equiangularly spaced holes 34 in inner sleeve 13 to receive a major portion of the detent balls 35, and annular groove 36 in outer sleeve 14 to receive a small portion of the detent balls. Inner sleeve 13 forms an axial bore 54 in which firing pin 30 is slidably guided for movement to explode the fuse. Pin 30 is also provided with enlargement 31, central cylindrical guiding portion 31a to abut the wall of bore 54 soas to guide the tiring pin, beveled face 32 andforward reduced portion 33. A heavy backing or closure plate 55 is secured to cylinder 6 and abuts the main body portion of the fuse to close olf the forward end of bore 54. The tiring pin guide hub has been eliminated in this species and the firing pin is of larger diameter than in the before described species so that spring 29 is compressed in the annular chamber formed Vby the tiring pin and the inner wall of sleeve 13.

Referring to Figures 9 and 10 the operation of the device is as follows. In unarmed position, tiring pin 30 directly abuts plate 55, to compress spring.29 between plate 54and the forward face of enlargement 31, and the Yet centrifugal force responsive mechanismsfis in :inwardly locked position so that the ends ofdpins 44 and 45 abut the forward -zendof sleevefl'4 to Flock fthis sleeve rear- Wardly in recess 11. Detent balls 35 ,are also pressed rearwardly by spring and beveled face32 and are retained "'inholes 34 and-grooves 36. The-springsfSZ and53 in the centrifugal force responsive-mechanism are calibrated-so that the force required -to-compress lthem and the-friction Ibetweenthe sloped-wallse-off'bores'40 and 41 and -sleeves 48 and 49 are suicientto.retaintheparts in locked position until setback -c`eases,'hence on'setback the parts are in position :as .seen in .Figure 9, with the iring'lpin and sleeve' 13f1abutting .plate 55. vDue tozthe inclination of bores 40 and 41, setback also tends to increase the frictional force between the locking pins and corresponding bore walls.

Upon cessation of setback, centrifugal force compresses the springs in the centrifugal force responsive mechanism and the pins are withdrawn so that they no longer abut the forward end of sleeve 14.v The fuse is now in semiarmed position and sleeve 14 is prevented from creeping forwardly by the anti-creep device, as previously explained. Upon impact, the resistance of the detent balls in groove 36 is overcome and sleeve 14 is forced forwardly to abut plate 55. 'Ihe fuse is now completely armed so that when inertia due to impact force is overcome spring 29 expands and the pressure exerted by beveled face 32 of the firing pins forces the detent balls into the unoccupied rear end of recess 11 to release the firing pin to forceably drive the firing pin rearwardly and into contact with the detonator (not shown) in the projectile casing. The relative position of parts following cessation of impact forces is clearly seen in Figure l0.

The species illustrated by Figures 9, l0, and 1l, eliminates the ring pin guide hub, however, it is within the contemplation of this disclosure to include this expedient similarly as in the first described species. Other modifications and alterations of the structure which has been disclosed herein for purposes of illustration will be apparent to one skilled in the art, and it is obvious that the same may be made without departing from the spirit and scope of the invention as defined in the following claims.

We claim:

l. In a projectile fuse, a firing pin moveable from safe position to armed position at impact and to firing position after impact, resilient means biasing said pin into tiring position, a detent means jointly coacting with said detent to lock said firing pin in safe position, said locking means, said pin and said detent being unitarily moveable at impact against the bias of said resilient means to move said pin to armed position, means normally immobilized by said detent and moveable at impact to free said detent for movement to position to release said firing pin, and means after impact including said resilient means actuable to move said detent to position to release said tiring pin, whereby said resilient means propels said pin to firing position.

2. The combination in claim l wherein said projectile is spin stabilized, means responsive to set-back forces normally engaging said detent immobilized means and additionally securing said pin in safe position, said set-back responsive means being also responsive to centrifugal force at cessation of set-back to disengage said detent immobilized means.

3. In a projectile fuse, a firing pin moveable from safe position to armed position at impact and to ring position after impact, resilient means biasing said pin to tiring position, a detent, first and second elements jointly co-acting with said detent to lock said pin in safe position, said first element, said second element, said firing pin and said detent being unitarily moveable at impact against the bias of Vsaid resilient means to move said firing pin to armed position, said second element being also responsive at impact to free said detent for movement to position to release said tiring pin, and means after impact including saidresilient; means ,actuable-to release :said ring pinfrom said detent and-.said .rst element, whereby said `resilien means propels said ring pin to firing position.

4. The Vcombination in claim 3 wherein said `projectile Vis spin:stabilized, means responsive to set-back forcesengaginggsaid second elementyand additionallygsecuring said pin in safe position, `said rsiet-back responsive means being also responsive toicentrifugal force at cessation of set-,back todisengage said first element.

5. Ina fuse, afring-pin moveable from safe `position 0to armed position at impact Yand lto tiring `position after gimpact, resilient means biasing said 4pinto vfiringV position, a detent, Afirst fandl second Ysleeves Vconcent-riclwith` Asaid'ftiring pin jointly co-acting with said detent and said resilient means to lock said firing pin in safe position, said rst and second concentric sleeves, said detent and said firing pin being unitarily moveable at impact against the bias of said resilient means to move said firing pin to armed position, means responsive to impact to release said second sleeve from said detent, and means after impact including said resilient means actuable to release said pin from said detent and said first sleeve for movement to firing position.

6. The combination in claim 5 wherein said projectile is spin-stabilized, means responsive to set-back forces for engaging said second sleeve and additionally securing said tiring pin in safe position, said set-back responsive means being also responsive to centrifugal force at cessation of set-back to disengage said second sleeve.

7. A fuse according to claim 5 wherein said detent cornprises an enlargement on said tiring pin engaging the inner wall of said first sleeve and having a' beveled surface, and a plurality of equiangularly spaced detent balls abutting said bevelled surface and extending through radially alined holes in said inner sleeve to rest in a circumferential groove in said outer sleeve.

8. In a fuse for a projectile, a firing pin moveable from safe position to armed position at impact, and to ring position after impact, a detent, inner and outer sleeves concentric about said tiring pin jointly co-acting with said detent to lock said pin in safe position, resilient means within said inner sleeve biasing said pin to firing position, said inner and outer sleeves, said detent and said tiring pin being unitarily movable at impact to armed position against the bias of said resilient means, means responsive to impact to release said outer sleeve from said detent and said inner sleeve, and means after impact including said resilient means to release said pin from said detent and said inner sleeve for movement to firing position.

9. The combination in claim 8 wherein said projectile is spin-stabilized, means responsive to set-back for engaging said outer sleeve and additionally securing said pin in safe position, said set-back responsive means being also responsive to centrifugal force at cessation of set-back to disengage said outer sleeve.

10. A fuse according to claim 8 wherein said detent comprises an enlargement on said tiring pin engaging the inner Wall of said inner sleeve and having a beveled surface, and a plurality of equiangularly spaced detent balls labutting said beveled surface and extending through holes in said inner sleeve to rest in a circumferential groove in said outer sleeve.

l1. In a deceleration activated spin stabilized fuse for a projectile, a body portion, an axial bore in said body portion, inner and outer concentric sleeves forwardly axially slidable in said bore, a ring pin reciprocable within said inner sleeve from safe position forwardly to armed position at impact, then rearwardly after impact to firing position, resilient means biasing said pin into tiring position, a'detent, said inner and outer sleeves jointly co-acting with said detent to lock said ring pin in safe position, said inner and outer sleeves, said detent and said firing pin being unitarily slidable at impact to armed position, means responsive to impact including additional forward movement of said outer sleeve for releasing said outer sleeve from said detent and said inner sleeve, and means after impact including said resilient means responsive to said additional forward movement for releasing said pin from said detent and said inner sleeve for movement to ring position. l

12. 'Ihe combination in claim 11 including means relsponsive to set-back forces to engage said outer sleeve for additionally securing said pin in firing position, said set-back responsive means being also responsive to centrifugal force to dsengage said outer sleeve.

13.I A fuse according to claim 11 wherein said detent comprises an enlargement on said firing pin engaging the inner wall of said inner sleeve and having a beveled surface, and a plurality of equiangularly spaced detent balls abutting said beveled surface and extending through holes in said inner sleeve to `rest in a circumferential groove in said outer sleeve.

References Cited in the .file of patent.

UNITED STATES PATENTS 

